This invention relates to an automatic open-structure machine tool which can be converted into a closed-structure machine tool such as a gantry machine or a mobile-crosspiece machine, following which the original configuration can be restored when required.
This is a machine of the type comprising a track along which runs an upright with a projecting crosspiece (axis X); a support which houses a sleeve runs along the crosspiece (axis Y), and an operating head is fixed to the sleeve, which moves along a vertical axis orthogonal to the previous ones (axis Z).
The machine is designed so that a connector with sliding shoes can be fitted to the end of the mobile crosspiece, together with an auxiliary motor (if required), to connect that end of the crosspiece to a structure, also forming part of the invention, which consists of a monolithic truss with a guide along which the said connector fixed to the crosspiece runs.
As part of the invention, a seating is cut into the upright of the mobile structure for the insertion of suitable counterweights designed to balance the weight of the projecting parts, in order to limit the deformation of the structure when the machine is used in the open configuration.
An open-structure machine is known from the application no. PC91 U 000002 dated 21st January 1991 filed by the same applicant; a side view of that machine is shown in FIG. 1.
That machine comprises a base 1 with a pair of guides 2 along which moves a structure comprising an upright 3 with a projecting crosspiece; along the said crosspiece runs support 5 of a sleeve 6 which is fitted with an operating head with several degrees of freedom equipped with an electric chuck with connector for an interchangeable tool.
This describes the state of the art to date.
At times, however, situations arise in which it would be useful to have a machine with a closed structure, such as a mobile-crosspiece machine, ie. one with a crosspiece which moves along a pair of rails and supports the tool-holding sleeve, or a gantry machine in which a gantry structure moves along a pair of rails and always supports a sleeve with the operating head.
Many companies require an open-structure machine for most applications, but in some cases would find it useful to have a closed-structure machine tool, although this need is not so frequent as to justify the cost of purchasing a second machine.